Welcome back to "Doggerel," where I ramble on about words and phrases that are misused, abused, or just plain meaningless.
There's a very simple thing to say about this bit of doggerel: There's no such thing as "100% safe." That's what makes it so favored by scaremongers for a type of goal post moving: The impossible standard.
One problem often inherent to mankind is the inability to properly evaluate risk. People often worry about highly improbable but dramatic dangers than they do about the mundane, everyday hazards of living. That's why, for example, anti-vaxxers will latch onto any unlikely perceived danger in vaccines while ignoring the potentially lethal effects of the diseases they prevent. They also tend to ignore the everyday small, safe doses of the toxins in our food, produced naturally in our bodies, or even necessary to live. (The dose makes the poison, after all)
Life is messy. Science has advanced our way of life to the point that most of us take health and safety for granted. We can afford to drive to work because safety tests ensure our cars' seat belts, crumple zones, and air bags will protect us, police enforce speed limits, lights and signs regulate the flow of traffic, and so on and so forth. The same is essentially true for food and medicine in developed nations. Dedicated individuals do their part so that we don't have to expend as much effort on everyday health decisions: They do all the analysis work on risks and benefits for us.
Of course, I'm not advocating leaving it all to the regulatory agencies. If you have some condition you need to be treated for, you should read up on it, ask questions, and so forth. Just be cautious if someone trying to sell you something whines excessively about small risks or promises complete safety. That's the other aspect of this doggerel: The Perfect Solution Fallacy: Just because the most reliable methods fall short of absolute perfection isn't reason to reject them.